Landing: 465ee014cb0c

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Project / Subsystem

gcc / gcc/middle-end

Date

2026-08-13

Author

Richard Biener

Commit

465ee014cb0cf9be62f0fd3de3821c755d37f58d

Source

github

Perf win

Yes

Breaking

No

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All attributes

project: gcc
subsystem: gcc/middle-end
patch_id: —
commit_hash: 465ee014cb0cf9be62f0fd3de3821c755d37f58d
source_type: github
headline: Improve vector conversion folding by handling NOP and sign conversions correctly.
tldr: Vector conversion optimizations now correctly handle no-operation and sign-preserving conversions.
author: Richard Biener
outcome: committed
performance_win: true
breaking_change: false
series_id: —
series_parts: []
tags: • optimization
• vectorization
• middle-end
• type conversion
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/465ee014cb0cf9be62f0fd3de3821c755d37f58d
date: 2026-08-13T00:00:00.000Z

This commit refines vector conversion optimizations by addressing issues in supportable_convert_operation and vectorizable_conversion. It ensures that no-operation (NOP) conversions and sign-preserving conversions are correctly handled, preventing test suite failures. The changes allow NOP_EXPR and VIEW_CONVERT_EXPR for same-mode types, and modify vectorizable_conversion to prefer VIEW_CONVERT_EXPR for vector types, ensuring that these conversions are recognized and optimized appropriately without introducing incorrect behavior.